Two-step relay



Aug. 24, 1943. R. L. PEEK, JR

TWO- STEP RELAY Filed Sept. 23, 1942 INVENTOR R. L. FEE/('3 ATTORNEY Patented Aug. 24, 1943 orsicc 7 TWO-STEP Robert L. Peek, In, Short Hills, N.

Bell Telephone Laboratories, New York, N. Y.,' a corporation of Application September 23, 1942,

7 Claims.

This invention relates to relays and more particularly to relays for use in the circuits of tele phone systems.

It is sometimes desirable in the circuits of telephone or other systems to provide relays which are so designed that certain of the contacts thereof are operable upon one degree of energization of the relay coil and that other contacts are only operable upon a greater degree of energization of the cOil. Such relays are generally known as twostep relays. Relays of this general type have heretofore been proposed for use on subscribers lines of telephone systems to perform the dual function of line relays and cut-off relays. The line relay usually associated with a subscribers line of the step-by-step dialing switching system, for example, hastwo pairs of normally open contacts which become closed when the line relay winding is energized over the calling line loo-p upon the removal of the substation receiver from the swi-tchhook when the subscriber initiates a call, one pair of which contacts are effective to establish the line finder start circuit and the other pair of which are effective to connect the winding of the cut-on relay to the test sleeves of the line appearing in the banks of all line finders having access to the line. The associated clltiT relay is provided with one pair of normally open contacts and two pairs of normally closed contacts, the latter contacts being in the circuit of the winding of the line relay and effective when the cut-off relay winding is energized in response to theseizure or" the line by a started line finder to disconnect the line relay from the calling line loop and the former contacts serving to establish a holding circuit for the cut-off relay to hold it operated following the release of the line relay and until the connection is released and the line finder is restored to normal. This is only one specific use to which a relay of the type disclosed in this application might be put.

It is apparent that with an adequate design, a relay structure can be constructed, the armature of which is operable in a certain manner or to a certain amount upon one degree of energization of the relay Winding over one circuit, for example, over the subscribers line loop, to close certain of its normally open contacts and the armature of which is operable in a certain other manner or to a greater amount upon a further degree of energization of the relay winding over another circuit, for example, over the line finder test circuit, to close other of the normally Open contacts andto open others of its normally closed contacts.

5., assignor to Incorporated,

Yew York T7 Serial no.

nection with the It is therefore the object of the present invention to provide a relay simple in structure and efiicient in operation which will be operable in two very definite steps. To attain this object, an E-shaped field piece with a coil surrounding its middle or core arm is provided with a spring supported armature attractablc to the forward ends of the three arms, the armature being attracted in a linear motion to the three arms upon a partial energization of the coil and subsequently attracted by a rocking motion on the middle arm as a fulcrum to one of the outer or return pole-piece arms upon a stronger energization of the coil.

The operation and structural details of the improved relay constructed in accordance with the invention will be more readily understood from the following detailed description taken in conaccompanying drawing in which:

Fig. 1 is a side elevational View of the relay;

Fig. 2 is a bottom plan view of the relay;

Fig. 3 is an end elevational view of the relay taken along the section line 3-3 of Fig. 1 showing the armature in its normal unettracted position;

Fig. 4 is a similar endelevational View with the armature shown in first step attracted position;

Fig. 5 is a similar end elevational view with the armature shown in its second step attracted position;

Fig. 6 is a, partial bottom plan view of the relay showing the manner in which the armature supporting spring is flexed when the armature assumes its second step attracted position; and,

Fig. 7 is a detail View of the armature.

The relay has an E-shaped field piece of magnetic material having three forwardly extending arms I, 2 and 3 and a bracket portion 4 bent at right-angles from its rear edge to serve as a support, for the relay upon a suitable i iounting rack.

An energizing coil 5 having a front spoolhead 6 provided with the usual side notches for positioning the fixed springs of the spring pile-ups of the relay and rear spoolhead "l is supported on the middle or corearm 2 and within the two outer or return pole-piece arms I and 3 of the field piece. Supported on one face of the rear end of the field piece and separated therefrom by the spacer 8 is a reed. spring member 9 preferably of hard nickel-silver. The member 8 is of substantially rectangular formation having a wide rear portion by which it is supported on the spacer B, a front portion ti] and two side arms H and IL. The front portion 10 is cut away eachend springs r i i V x For operating the movable or armature springs thereof to form two cars is and M to which the transversely extending armature 65 is secured by the eyelet rivets it and ii.

Supported on the rear end portion of the spring member d and insulated therefrom by in-' terposed strips $8 of insulating material are two coil terminal lugs 25. Supported on the other facevof the rear end of the field piece opposite the two side arms i and 3 are two spring pileups.. Each of the spring pile-ups may comprise any desired number and arrangement of contactsprings but since it is assumed that the relay disclosed is expressly designed for use as a combined line and cut-off relay assembly, the upper spring pile-up comprises one pair of normally the field piece.

open contactsprings including one movable or I armature spring 29 and one fixed spring 2! and the lower spring pile-up comprises one pair of' normally open contact springs 22 and 23 and two pairs of normally closed contactsprings 2d and 25 and 2t and 2?, of whichspringsZZ, 25 and 2'! are movable or armature springs and springs 23, 24 and 26 are fixed springs.-

- The coil terminal lugs l9, the spring-member 9, the spacer fifthe spacers 28 and'the spring pile-,ups are suitably clamped to the rear end of 1 the field piece by screws Edwhich pass through holes in the clamping-plates 36, in the insulating I strip 3i, in the lugs it, inthe insulating strips, 7 7 it, in spring member 9, in the'spacing plates,

in the field-piece, in the spacers 28, in the ins ulating strips 32 and in the contact springs into threaded holes in the clamping plates 33. The terminal lugs l9 and the contact springs are insulated from each other, from the field piece and from the clamping plates 3% and 33 by the in- The armature l5 is'bent into the shape best disclosed in Fig. 3 with its central portion so bent that normally the air-gap between the pole face of its central portion and the pole, face of the core arm 2 of the field piece is narrower than the air-gaps between its two end portions and the pole faces of the return pole-piece arms l and 3 of the field piece. Stop discsdl of nonmagnetic material are welded or otherwise secured to the pole faces of the armature at points opposite the pole faces of the arms l, 2 and 3 of As best disclosed in Fig. 7, the cross section of the armature is reduced at one end adjacent to its center portion by the notches 52 for the purpose of restricting the magnetic flux which can flow through that end of the armature.

The structural details of the relay having now been described, the manner in which the relay functions will be discussed. With the relay coil fid'eenergized, the armature is'held by the pressure of the armaturespri'ngs of the spring pile- .ups in the position disclosed in Fig. 3' in which position the tongue El i-of the spring member ii is engaged againstthe'backstop nut 35 and the two end portions of the armature are equally spaced from 'the pole faces of'the return'polepiece arms l and 3. When now the coil 5 is partially energized the-armature l5 is'attracted in a linear movement untilthe stop disc ll on the central portion of the armatureengages the pole face of the core arm 2 and the end-portions of the armature are nearer to the pole faces ofthe return pole-piece arms land 3 but still separated therefrom' by equal air-gaps. It will'beassumed that the initial energization of the coil ais'not terposedinsulating strips I8, 35 and 32 and-the clamping screws29 have their shanks surrounded by the usual sleeves of insulating material (not shown) for insulating them where they extend through holes in the coil terminal lugsand in the contact springs.

The movable or armature springs have their contact ends bifurcated with each sectionthus formed provided with a contact bar and each mating or fixed spring is provided with a pair of I cooperating contact barswhereby doublecontacts'are provided between each pair of mating the armature spring 28 has a stud 3'! of insulating material ring-stakedthereto with its inner end engaging against the innerface of the side portion H of the spring member 9,the armature spring 22 has a stud 38 of insulating-material ring-staked to an inwardly extending arm thereof and engaging against the armature l5 adjacent the center portion thereof and the armature spring 2 3 has a stud iii) of insulatingmaterial ring-staked thereto and extendingfreely through holes in the armature spring .22 and the fixed springs 231d and 26 with the inner end thereof engaged against the inner face of the side portion 12 of the spring member 9 and the outer end thereof engaged against the armature spring 27. The forward or free end of the spring member 9 is provided withefbifurcated tongueportion" (idwhich freelyembraces the backstop screw 35.

jThe screw 35'is secured to the end of the core arm; of the field piece and has threaded thereon a backstop nut 36 which serves as a' backstop to limit the releasing movement of the armature l5 and to adjust the normal air-gaps between the armature and the ends of'the arms M2 and 3 of'the field'piec'e.

sufiicient'to further operate the armature. f The armature is nowin its first stepoperat'ed position shown in Fig. l, in which position the armature presses upon the operating studstland 38 to cause the engagement of armaturespring 2G with its mate spring 25 and to cause the engagement of the-armature spring 22 with its mate ispringZb. 'The movement of the studetl is not, however, suficient to cause the armature springs 25 and 2? to disengage their mate-springs 2 5 and 25. At'this time the fluxfiowingthrough the upper end .of the armature as viewed in Fig. 4 to the return pole-piece arm l substantially 'saturates the armature at its restricted por tion between the notches 62. I

If the coiliEi now becomes fully energized, the

7 increased flow of flux through the armature due to the saturated condition of therestricted portion of the armature is directed acrossthe airgap between the lower end of the armature, as

viewed in Fig. l, and the'pole-piece arms 3, and since the stop disc ll on the central portion of the armature is engaged against the pole face rocking movement, the upper end of the armature has been moved away from the upper polepiece arm' i the pressure upon the stucl'l'i isjrelieved to permit spring tc become disengaged from its mate spring 2%. V

When the coil 5 becomes decnergizcd, the relay armature returns to its normal position illustrated in Fig, 3.

If the relay is employed a combined line and cut-of relay a circuit of the type previously described, the coil may be energized in a first circuit over the calling line loop to operate the armature in its first step to engage spring 28 with spring 2! to establish the line finder start circuit and to engage spring 22 with spring 23 to prepare a second operating circuit for the coil 5 over the test tern ial multiples in the banks of line finders having access to the calling line. When the line finder finds the line, coil 5 becomes more strongly energized over this second circuit to operate the armature in its second step where-- upon springs 22 and 2,5 are maintaincd in em gagement to hold the second operating circuit of the coil 5 closed, to disengage springs 25 and 2! to open the line finder start circuit an: to disengage springs 25 and 2? from springs 2.5 and 26, respectively, to disconnect the coil 5 from its first energizing circ it over the line loop. Since invention primarily relates to structure the improved relay and not to any to cuit applica on thereof, the circuit apolicatic above described has not been illustrated.

Structures other than that above d ibmay be employed to obtain the s"- of two-step operation, as the c y el ential requirements are the provision of two alternative magnetic paths, armature capable of closing only one of these paths at a time and a constriction limiting the flux that pass through one of the paths.

What is claimed ment on the middle one of said contact springs selectively operable in to the two movements of armature, an onergizing coil surrounding the one of said arms operable upon its partoneration to cause the linear movement of said armature and operable upon a stronger energization to cause the further rocking movement of said sure.

2. In a relay, an E- haped field piece, an armature extendiug transversely no .orward ends of the pole-piece arms of said field piece, a spring member secured at one end to the rear end of said field piece having two forwardly extending arms scour u. at their forward ends to the ends of said armature, whereby said armature is free to move in a linear movement into engagement with the KP ilo one of said pole-piece arms and is free to thereafter move in a rocking mover" at about said middle pole-piece arm as a iulcru into e agemont with one of said other polo-piece contact springs selectively operable in response to the two movements of said armature, and an energizing coil surrounding the middle one of said pole-piece arms and operable upon partial energization to cause the linear movement of said armature and operable upon a stronger energization to cause the further rocking movement of said armature.

3. In a rela an E-shap piece, an armature extenoing transversely across the forward ends of the pole-piece arms of said field piece, said armature being reduced in cross-scctional area at a point on one side of its center,

whereby the flux carrying capacity of that end of said armature is reduced, a spring member for supporting said armature to enable a linear movement thereof toward said pole-piece arms and a rocking movement on the middle one of said arms, contact springs selectively operable in response to the two movements of said armature, and an energizing coil surrounding the middle one of said arms and operable upon its partial energization to cause the linear move ment of said armature and to cause the magnetic saturation of the constricted portion of said armature and ope "able upon a stronger energization to cause the further rocking movement of said armature.

4. Ina relay, an E-shaped field piece, an armature extending across the forward ends of the pole-piece arms of said field piece, said armature having the pole face of the central portion thereof extended beyond the plane of the pole faces of its end portions whereby the airgap between said central portion and the middle arm of said field piece is narrower than the air-gaps between the end portions of said armature and the outer pole-piece arms of said field piece, a spring member for supporting said armature to enable a linear movement thereof toward said pole-piece arms and a rocking movement on the middle one of said arms, contact springs selectively operable in response to the two movements of said armature, and an energizing coil surrounding the middle one of said arms and operable upon its partial energization to cause the linear movement of said armature and operable upon a stronger energization to cause the further rocking movement'of said armature.

5. In a relay, an E-shaped field piece, an armature extending transversely across the forward ends of the pole-piece arms of said field piece, said armature having the pole face of the central portion thereof extended beyond the plane of the pole faces of its end portions whereby the airgap between said central portion and the middle arm of said field piece is narrower than the air-gaps between the end portions of said armature andthe outer pole-piece arms of said field piece, said armature being further provided with oppositely disposed notches to provide a reduced cross-sectional area between said central portion and one of said end portions whereby the fiux carrying capacity of that end of the armature is reduced, a spring member for supporting said armature to enable a linear movement thereof toward said pole-piece arms and a rocking movement on the middle one of said arms, contact springs selectively operable in response to the two movements of said armature, and an energizing coil surrounding the middle one of said arms and operable upon its partial energization to cause the linear movement of said armature and to cause the magnetic saturation of the constricted portion of said armature and operable upon a stronger energization to cause the opposite end portion of said armature to be rocked toward the associated pole-piece arm.

6. In a relay, an E-shaped field piece, an armature extending transversely across the forward ends of the pole-piece arms of said field piece, a spring member for supporting said armature to enable a linear movement thereof toward said pole-piece arms and a rocking movement on the middle one of said arms, a first pair of normally gaged contact springs positioned beneath the other end of said armature, studs operable by the movement of said armature for operating said :pairs of contact springs, and an energizing coil springs and to disengage said two pairs of norinally engaged contact springs while maintaining second pair of contact springs engaged.

V 7. In a relay; a field piece having a plurality of pole pieces'providing two alternative paths for the'fiow of flux therethrough, an armature attractabie to said pole pieces to close either one of said flux paths, one of said flux paths having a portion constricted in cross-sectional area Wherebythe flux carrying capacity of that path is reduced, a spring member for supporting said armature, and an energizing coil associated with said field piece and operableupon its partial energization to cause an attraction of said armature to close one of said flux paths and to cause the magnetic saturation of said constricted portion of said path and operable upon a'stronger energization to cause the further attraction of said armature to close the other of said flux paths;

ROBERT L. PEEK, JR. 

